Process of making corrugated furnaces and flues for steam-boilers.



PATENTED JULY 4, 1905.

G Kr W. RAINFORT E. GEARIN PROCESS OF MAKING CORR ATED FOR STEAMBOILERS.

APPLIUATI FURNACES AND PL 0N FILED PEB.16, 1904.

3 SHEETS-SHEET 1.

Wwwwww No. 794390. PATENTED JULY 4, 1905. E. GEARING & W. RAINPORTH.

PROCESS OF MAKING CORRUGATED FURNACES AND FLUES FOR STEAM BOILERS.

APPLICATION FILED P131316. 1904.

3 SHEETSSHBET 2 PAT ENTED JULY 4, 1905. En GEARING 6:; W. RAINPORTH.PROCESS OF MAKING CORRUGATED FURNACES AND FLUES FOR STEAM BOILERS.

APPLICATION FILED FEB.16, 1904.

3 SHEETS-SHEET 3.

no. "re roeo.

t i i it lirtli Patented July 4., 19*05.

.litii-tiliithiit itji rriicn.

IlC'hNFtl'l ('ii iAHlNtir, OF .llJUtRUGrATE, Altl) WlLLlAhl hJilNFOHlTU, OF LEEDS, ENGLAND.

PROCESS OF lVli-lKlilG CORRUGATED FURNACES AND FLUES FOR STEAM-BOILERS.

EdPEGIFIGATION formingpart of Letters Patent No. tw rl-Q90, dated July4, 1905.

Application filed February 16, 190&. Scria11l0.l93,867.

To It whom/ it 'nwty con/corn:

Be it known that we, lt'imns'r (-inau mo, resid ing at Llarrogate, andFFILLIAM lltAINroi-mi, residing at Leeds, in the county of York,England, subjects oi the King o I Great Britain and lreland, haveinvented a Process oi. lt laking Corrugated Furnaces and Flues iorSteam- ,lioilers, of which the 'iollowing is a spcciiication.

ll itherto it has been impracticable to roll in a plain tube steep-sidedhollow outwardlyprojectil'ig strengthening portions or ribs(llfli'flillililltl called hollow ridges) oi adequate depth to ailordthe requisite strength to withstand modern wor lug boiler-pressuresbecause of the thinning oi portions oi the wall when the attempt made toroll deep steepsided ridges in the ordinary manner.

Now the object oi this invention is to produce from a plain tube and byrolling a steamboiler furnace or line having deep steep-sided hollowridges without rendering any portion oi the furnace or line wall undulythin. For this purpose hollow ridges tormeiil on a tube by a preliminarycorrugating process are converted to the required section by theapplication of rolling pressure to the tube-wall in a direction normalto the axis oi the tube and in such wise as to reduce the depth oi thehollow ridges from their summits to the bottoms oi the valleys and bythe application oi sure to the opposite sides oi iiulividual ges, theresult being that the Valleys are widened and the sides oi each ridgecaused to approach each other. Usually the preliminary corrugatingprocess is ei'lected in two stages, and the ridges formed by thepreliminary corrugatil'ig process are given the rcquired shape by oneormore sets oi compound collapsible and GXlHtllLlllilU segmental iorl'nersthat are adapted when in the collapsed condh tion to enter the valleysbetween the hollow ridges on the exterior oi the furnace or ilue and arethen during the rotation oi the iurnace or line by suitably corrugatedor ribbed internal and external main rolls adapted to reduce the depthoi the ridges, expanded sidewise, so as to embrace the hollow ridge.between them and simultaneously press the side portions oi each ridgetoward each other, the shape oi the ioriners being such that there isbetween each adjacent pair a space or groove correspoi'iding incross-sectional shape to that which it is desired to impart to eachhollow ridge, so that by the COiltillllOtl rotation of the furnace orline the whole oi the hollow ridges thereon will be simultaneouslypressed to the required i'inished shape, the valleys between them beingwidened without altering the pitch oi the ridges.

In the accompanyingdrawings, Figure l is a sectioiiial View oi acorrugated partially" iormed tul )ewall. Fig. 2 shows the sameformation, but indicates the application thereto 01 the rolls used toimpart to the tube-wall shown in Fig. l the formation shown in Fig. 3.The left and right hand portions of the iigure, respectively, show therolls at the coml'nencement and end oi. their operation. Fig. 3 is asimilar View to Fig. 1 of the tube-wall a'i ter having been subjected toa two-stage preliminary corrugating process, the second stage beingeii'ected between the rolls indi cated in Fig. 2. Fig. +i.- illustratesthe application oi the rolls to the formation shown in Fig. 3. in theleft-hand portion the rolls are shown in the positions they occupy atthe comnu'niccmentoi their operation, and in the righthand portion theyare shown in the positions they occupy at the end oi their operation.Fig. t illustrates the application oi the tormers to the im-mation shownin Fig. 3. in the leit-lial'id portion oi the iigure the 'iormers areshown in the positions they occupy at the commencement oi theiroperation, and in the righthand portion they are shown in the positionsthey occupy at the end oi their operation. Fig. 5 shows the formationresulting irom the operation oi the rolls and formers. Figs. 6, 7, t5,and 9 illustrate, respectively, theoriginal plain tube and the same tubeaiter the preliminary corrugatii'lg operation, the same tube alter thedepth of the ridges has been deep-- ened and their sides steepcned, andthe completed i'uruzuze or line tube.

The furnace or 'i'lue tube is preierably iirst rolled in stages to thesectional iorm shown in Fig. 3, the iirst rolling operation forming deepand wide but not steep-sided corrugations, as shown in Fig. l, and asubsequent rolling operation applying pressure (b y means of an internalroll 0 and an external roll (Z, as indicated in Fig. 2) in a directionnormal to the axis of the tube to the sides of the ridges or outwardcorrugations a, so as to steepen and deepen the ridges without alteringtheir pitch and widen the intermediate valleys, giving to the flue-wallsubstantially the sectional form shown in Fig. 3. The application ofrolling pressure to a tube-wall of the form shown in Fig. 3 and normallyto its axis and of pressure to the sides of individual ridges by meansof formers 71/ is illustrated in Figs. L and 4:. It will be seen fromFig. that the rolls 0 and (Z reduce the depth of the ridges. They alsoslightly increase the smallest internal diameter and slightly decreasethe greatest external diameter, thus causing the wall of the flue tomove a little toward the formers, which are situated to one side of therolls. This movement is indicated in Fig. 4c. The linal formation of thetube-wall (shown in Fig. is produced by the closing up of the rolls,illustrated by Fig. a, and the expanding of the formers b by means ofwedges 5 while the tube is rotated by the rolls, as illustrated by Fig4:.

In this specification and in the claims we use the expression pressureto the side portions of the individual ridges and the expressionpressure in a longitudinal direction, and for thepurpose of illustratingour process we have shown diagrammatically an arrangement of devicesadapted to exert pressure against the respective side walls of a hollowridge in opposite directions parallel to the tube-axis, which weconsider to be the best; but it is a feature of our invention that inaddition to the pressure in planes substantially at right angles to theaxis of the tube under treatment there is exerted against the side wallsof the hollow ridges other pressure, such as cannot be exerted by thesame rolls which exert the pressure in the planes substantially at rightangles to the axis of the tube. This being so, it will be understoodthat the respective expressions pressureto the side portions of theindividual ridges and pressure in a longitudinal direction are not usedby us in the sense of limiting ourselves strictly to pressure in adirection parallel to the tube-axis, but are intended to include asequivalent of such pressure any pressure not exerted by the inner andouter rolls which will have the effect of reducing the distance apart ofthe two side walls of a hollow ridge. Thus, for example, it will beobvious that, assuming formers having grooved cheeks adapted to beturned slightly about axes at right angles to the tubeaxis instead ofbeing adapted to slide parallel to said axis be employed, the etlect ofwedge action would be to cause the formers to move 5 the side walls ofindividual ridges nearer together.

hat we claim is 1. Theherein-described process of treatingpartially-formed hollow strengthening-ridges in the wall of a furnace orfine tube which consists in the application of rolling pressure to i thetube-wall in a direction normal to the axis of the tube so as to reducethe depth of the ridges and intermediate valleys, and of pressure to theside portions of the individual ridges so as to press the side portionsof each ridge toward one another.

2. The herein-described process of treating partiallyformed hollowstrengtheningridges in the wall of a furnace orflue tube which consistsin the application of rolling pressure to the tube-wall in a directionnormal to the axis of the tube so as to reduce the depth of the ridgesand intermediate valleys, and of pressure to the side portions of theindividual ridges in a longitudinal direction so as to press the sideportions of each ridge toward one another.

3. The herein-described process of treating partially-formed hollowstrengthening-ridges in the wall of a furnace or flue tube whichconsists in the application of rolling pressure to the tube-wall in adirection normal to the axis of the tube so as to reduce the depth ofthe ridges and intermediate valleys, and of pressure to the sideportions of the individual ridges so as to press the side portions ofeach ridge toward one another, the pitch of the ridges being maintainedconstant.

partially-formed hollow strengthening-ridges in the wall of a furnace orflue tube which consists in the application of rolling pressure to thetube-wall in a direction normal to the axis of the tube so as to reducethe depth of the ridges and intermediate valleys, and of pressure to theside portions of the individual ridges in a longitudinal direction so asto press the side portions of each ridge toward one another, the pitchof the ridges being maintained constant.

5. The herein-described process of making a steam-boiler furnace or flueof the kind having hollow strengthening-ridges, which consists inrolling hollow ridges and intermediate valleys in the wall of a tube andafterward subjecting such tube-wall to a combined rolling and pressingoperation whereby pressure is applied to the tube-wall in a directionnormal to the axis of the tube and the depth of the ridges reduced andwhereby pressure is applied to the side portions of the individual'ridgcs so as to press the said side portions toward each other, as setforth.

6. The herein-described process of making a steam-boiler furnace or flueof the kind having hollow strengthening-ridges, which consists inrolling hollow ridges and intermediate l. The herein-described processof treating IIO reaeeo valleys in the wall of a tube and afterwardsubjecting such tube-wall to a combined rolling and. pressing operationwhereby pressure is applied to the tube-wall in a direction normal tothe axis of the tube and the depth oi? the ridges reduced and wherebypressure is applied to the side portions of the individual ridges in alongitudinal direction so as to press the said side portions toward eachother, as set forth.

T. The herein-described process of making a steam-boiler furnace or lineof the kind having hollow strengthening-ridges which consists insuccessively eorrugatii'ig the tube-wall by rolling, the pressure beingapplied normall y to the tube-axis, deepening and steepen ing the sideportions of the outward corrugations in the tube-wall by rolling, thepressure being a 'iplicd normally to the tube-axis, and afterwardsubjecting it to a combined rolling and n'essing operation wherebypressure is applied to the tube-wall in a direction normal to the axis01'' the tube and the depth of the ridges reduced and whereby pressureis applied to the side portions of the individual ridges so as to pressthe said side portions toward each other, as set forth.

8. .lhe herein-described process of making a steam-lmiler furnace orflue ot' the kind having hollow strengthening-ridges which consists insuccessively eorrugating the tube-wall plied to the tube-wall in adirection normal to.

the axis of the tube and the depth of the ridges reduced and wherebypressure is applied to the side portions of the individual ridges in alongitudinal direction so as to press the said side portions toward eachother, as set forth.

'9. The herein-described process of treating partially-formed hollowstrengthening-ridgcs in the wall of a furnace or llue tube whichconsists in the simultaneous application of rolling pressure to thetube-wall in a direction normal to the axis of the tube so as to reducethe depth of the ridges and intermediate valleys, and of pressure to theside portions of the individual ridges so as to press the side portionsof each ridge toward one another.

Signed at Leeds, county 01 York, England, this 1st day of liebruz'n'y190 i.

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